MRI study of radiation effect on Fricke gel solutions

Galante, A.M.S.; Cervantes, Hernán J.; Cavinato, Christianne Cobello; Campos, L.L.; Rabbani, Said

doi:10.1016/j.radmeas.2007.12.011

Cited by 31 publications

(5 citation statements)

References 7 publications

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“…Spontaneous oxidation. Spontaneous oxidation of Fe 2+ ions to Fe 3+ ions increases the R 1 of FXG dosimeters independently of applied radiation (Podgorsak 1989, Galante et al 2008, and occurs continuously from the time of FXG dosimeter manufacturing until all unreacted species of Fe 2+ are oxidized. After manufacturing, FXG dosimeters are typically refrigerated to slow the effects of spontaneous oxidation, and help set the gelatin matrix (Maryanski et al 1997, De Deene et al 2007, Schreiner and Olding 2009; however, spontaneous oxidation is not stopped completely.…”

Section: Empirical Model Motivationmentioning

confidence: 99%

The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry

Welch

Jaffray

2017

Phys. Med. Biol.

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Previously developed MR-based three-dimensional (3D) Fricke-xylenol orange (FXG) dosimeters can provide end-to-end quality assurance and validation protocols for pre-clinical radiation platforms. FXG dosimeters quantify ionizing irradiation induced oxidation of Fe ions using pre- and post-irradiation MR imaging methods that detect changes in spin-lattice relaxation rates (R = [Formula: see text]) caused by irradiation induced oxidation of Fe. Chemical changes in MR-based FXG dosimeters that occur over time and with changes in temperature can decrease dosimetric accuracy if they are not properly characterized and corrected. This paper describes the characterization, development and utilization of an empirical model-based correction algorithm for time and temperature effects in the context of a pre-clinical irradiator and a 7 T pre-clinical MR imaging system. Time and temperature dependent changes of R values were characterized using variable TR spin-echo imaging. R-time and R -temperature dependencies were fit using non-linear least squares fitting methods. Models were validated using leave-one-out cross-validation and resampling. Subsequently, a correction algorithm was developed that employed the previously fit empirical models to predict and reduce baseline R shifts that occurred in the presence of time and temperature changes. The correction algorithm was tested on R -dose response curves and 3D dose distributions delivered using a small animal irradiator at 225 kVp. The correction algorithm reduced baseline R shifts from -2.8 × 10 s to 1.5 × 10 s. In terms of absolute dosimetric performance as assessed with traceable standards, the correction algorithm reduced dose discrepancies from approximately 3% to approximately 0.5% (2.90 ± 2.08% to 0.20 ± 0.07%, and 2.68 ± 1.84% to 0.46 ± 0.37% for the 10 × 10 and 8 × 12 mm fields, respectively). Chemical changes in MR-based FXG dosimeters produce time and temperature dependent R values for the time intervals and temperature changes found in a typical small animal imaging and irradiation laboratory setting. These changes cause baseline R shifts that negatively affect dosimeter accuracy. Characterization, modeling and correction of these effects improved in-field reported dose accuracy to less than 1% when compared to standardized ion chamber measurements.

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Section: Empirical Model Motivationmentioning

confidence: 99%

The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry

Welch

Jaffray

2017

Phys. Med. Biol.

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“…The distribution of the resulting Fe 3+ is used to produce a 3D image of the absorbed dose by Magnetic Resonance Imaging (MRI) [6][7][8] or by optical imaging, provided that a suitable metallic-ion indicator is employed [9][10][11][12]. The most used metallic-ion indicator is Xylenol Orange (XO).…”

Section: Introductionmentioning

confidence: 99%

Characterization of radiochromic poly(vinyl-alcohol)–glutaraldehyde Fricke gels for dosimetry in external x-ray radiation therapy

Gallo

Artuso

Brambilla

et al. 2019

J. Phys. D: Appl. Phys.

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“…This uorescent strategy is unique from other uorescent dosimeters as well as Fricke dosimeters. [28][29][30] 2. Experimental section 2.1.…”

Section: Introductionmentioning

confidence: 99%

A rhodamine coumarin-derived fluorescence probe that selectively detects Fe³⁺ and measures radiation doses

Qin,

Han,

Jiang

et al. 2024

Anal. Methods

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MRI study of radiation effect on Fricke gel solutions

Cited by 31 publications

References 7 publications

The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry

The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry

Characterization of radiochromic poly(vinyl-alcohol)–glutaraldehyde Fricke gels for dosimetry in external x-ray radiation therapy

A rhodamine coumarin-derived fluorescence probe that selectively detects Fe³⁺ and measures radiation doses

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MRI study of radiation effect on Fricke gel solutions

Cited by 31 publications

References 7 publications

The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry

The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry

Characterization of radiochromic poly(vinyl-alcohol)–glutaraldehyde Fricke gels for dosimetry in external x-ray radiation therapy

A rhodamine coumarin-derived fluorescence probe that selectively detects Fe3+ and measures radiation doses

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Product

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A rhodamine coumarin-derived fluorescence probe that selectively detects Fe³⁺ and measures radiation doses